1. Field of the Invention
This invention relates to a panel structure for surface-discharge-type AC plasma display panels.
The present application claims priority from Japanese Application No. 2003-137270, the disclosure of which is incorporated herein by reference.
2. Description of the Related Art
Surface-discharge-type AC plasma display panels (hereinafter referred to as “PDP”) have recently gained the spotlight as types of large-sized slim color display apparatuses and are becoming increasingly common in homes and the like.
Such known surface-discharge-type AC PDP includes a three-electrode reflection-type PDP.
The structure of the three-electrode reflection-type PDP is described here. The front glass substrate is placed opposite the back glass substrate with a discharge-gas-filled discharge space in between. On the inner surface of the front glass substrate, a plurality of row electrode pairs and a dielectric layer overlying the row electrode pairs are provided. Each of the row electrode pairs is constituted of paired row electrodes (discharge sustaining electrodes) extending in the row direction and arranged parallel to another row electrode pair to form a display line. On the inner surface of the back glass substrate, a plurality of column electrodes (addressing electrodes) extends in the column direction. Discharge cells (unit light emission areas) are provided at each of the intersections of the column electrode and the row electrode pair in the discharge space. Further red-, green-, and blue-colored phosphor layers are provided individually in each discharge cell.
For the generation of an image on the three-electrode reflection-type PDP, first, an addressing discharge is caused selectively between the column electrode and one row electrode in the row electrode pair to generate a wall charge on the dielectric layer overlying the row electrode pairs or alternatively to erase the wall charge accumulated thereon. As a result, the discharge cells having the wall charge generated on the dielectric layer (lighted cells) and the discharge cells having no wall charge (non-lighted cells) a redistributed over the panel surface in accordance with the received image signal. After that, in each lighted cell, a sustain discharge is produced between the row electrodes in each row electrode pair. By means of this sustain discharge, vacuum ultraviolet light is emitted from xenon included in the discharge gas, and excites each of the red-, green- and blue-colored phosphor layers formed in the individual lighted cells to emit visible light for the generation of the image in a matrix display.
The conventional three-electrode reflection type PDP as structured in this manner is described in Japanese Patent Laid-open Application No. 10-321145.
The conventional structure of the three-electrode reflection-type PDP as described above requires a complicated manufacturing process for forming the electrodes separately on the front glass substrate and the back glass substrate, and a high degree of accuracy of the positional relationship of the electrodes between the front glass substrate and the back glass substrate. Therefore, this conventional PDP has the problem of the entailing high manufacturing costs and a further increase in costs due to the large number of components formed on each substrate.
On this account, a PDP having the row electrodes and the column electrodes both formed on a single glass substrate has been proposed for the achievement of cost cutting and of a finer resolution of the image display.
In the proposed PDP, a glass substrate placed opposite another glass substrate having a phosphor layer formed thereon has the double-layer structure of the row electrode pairs and the column electrodes which extend in a direction at right angles to the row electrode pairs being formed with the dielectric layer in between.
FIG. 1 is a front view showing the structure of a conventional PDP having the row electrode pairs and the column electrodes both formed on a single substrate.
In FIG. 1, on the inner surface of one of the substrates (not shown) of the PDP, row electrode pairs (X, Y) each constituted of the paired row electrodes X and Y extend in the row direction and are regularly arranged in plurality in the column direction. The row electrode pairs (X, Y) are covered with a first dielectric layer (not shown). On the inner surface of the first dielectric layer, bodies Da of a plurality of column electrodes D extend in the column direction and are arranged at regular intervals in the row direction. The bodies Da of the column electrodes D are covered with a second dielectric layer (not shown).
Each of the column electrodes D has discharge portions Db formed in the first dielectric layer, so that each of the discharge portions Db is flush with and opposite the row electrode X or Y of the row electrode pair (X, Y) to cause an addressing discharge in association therewith.
Discharge cells C are formed in each position opposite the area surrounded by the paired row electrodes X and Y and the two bodies Da of the adjacent column electrodes D, inside a discharge space defined between the two substrates.
Each of the row electrode pairs (X, Y) forms a display line L.
The foregoing surface-discharge-type AC PDP generates images as follows.
In a reset period, a reset discharge is produced simultaneously in each discharge cell C between one row electrode in the row electrode pair (X, Y) (in this case, the row electrode Y) and the discharge portion Db of the column electrode D. Then in the subsequent addressing period, an addressing discharge is produced selectively in the discharge cells C between the row electrode Y and the discharge portion Db of the column electrode D, whereby the lighted cells (the discharge cells C having wall charges generated on the dielectric layer) and the non-lighted cells (the discharge cells C having no wall charges generated on the dielectric layer) are distributed over the panel surface in accordance with the image to be displayed.
After the completion of the addressing period, a discharge-sustaining pulse is alternately applied, simultaneously in all the display lines L, to the row electrodes X and Yin each row electrode pair. Thereupon, due to the wall charges accumulated on the dielectric layer, a sustain discharge is produced between the row electrodes X and Y in each lighted cell with every application of the discharge-sustaining pulse.
As a result of the sustain discharge, ultraviolet light is generated from the discharge gas in each light cell, and excites each of the red (R), green (G) and blue (B) colored phosphor layers formed in the individual discharge cells C, to emit visible light for the generation of the images.
The conventional surface-discharge-type AC PDP structured as described hitherto has the following problems.
The reset discharge, the addressing discharge and the sustain discharge are all produced in the same discharge cell. Under these circumstances, the reset discharge and the addressing discharge excite the red (R), green (G) and blue (B) phosphor layers and therefore light emission from the phosphor is repeated. This light emission raises the brightness level when the display is black, which is a factor that lowers the light-dark contrast.
Further, the sustain discharge for visible light emission must be produced in the same discharge cell as that in which the reset discharge and addressing discharge preparatory to the light emission are produced. When the cell structure is designed, the necessity for compatibility between those discharges gives rise to considerable restrictions. This involves the problem of difficulties arising in providing the adequate discharge characteristics in any discharge.
In addition, in the conventional PDP, the addressing discharge produced in the same discharge cell C as that in which the sustain discharge is produced is affected by: the discharge characteristics varying among the individual phosphor materials of the colors of the phosphor layers formed in the respective discharge cells C; the change in discharge voltage traceable to the phosphor layers, for example, that is caused by variations in the layer thickness of the phosphor layers occurring when the phosphor layers are formed in the manufacturing process; and the like. For this reason, the conventional PDP has the problem of significant difficulties arising in providing equal addressing discharge characteristics in all the discharge cells C.